1. Technical Field
The present application relates to surgical clip appliers, and in particular relates to instruments having a plurality of clips for applying the clips to body tissues and vessels during surgical procedures.
2. Discussion of the Prior Art
Surgical clip appliers are known in the art and have increased in popularity among surgeons by offering an alternative to conventional suturing of body tissues and vessels. Typical instruments are disclosed in U.S. Pat. No. 5,030,226 to Green et al. and U.S. Pat. No. 5,431,668 to Burbank, III et al. These instruments generally provide a plurality of clips which are stored in the instrument and which are fed sequentially to the jaw mechanism at the distal end of the instrument upon opening and closing of the handles at the proximal end of the instrument. As the handles are closed, the jaws close to deform a clip positioned between the jaw members, and as the jaws are opened to release the deformed clip, a new clip is fed from the series to a position between the jaws. This process is repeated until all the clips in the series of clips have been used.
Surgical clip appliers in the prior art are known to include some type of lockout mechanism which prevents closing of the handles, and consequentially closing of the jaws if there are no clips present in the instrument. These lockout mechanisms prevent closure of the jaws about tissue, which can traumatize the tissue and perhaps cause serious damage to the tissue or vessel when a clip is not present in the jaws. However, many of the prior art instruments provide a lockout mechanism which interferes with the closure of the jaws, and upon the application of enough force to the handles, the lockout mechanism many times may be defeated. In order to prevent this, complex mechanisms are often provided, resulting in increased cost of manufacture of the instrument.
In addition, many of the prior art instruments provide complex mechanical arrangements for closing the jaws while simultaneously preparing for feeding the next clip into the jaws after the clip positioned between the jaws is deformed and then released. These complex mechanisms, such as that shown in U.S. Pat. No. 5,431,668 to Burbank, III et al., require numerous parts which increases the cost of manufacture, as well as increasing the time it takes to assemble each instrument. In addition, these instruments generally drive a first component, such as the channel assembly, in one direction to close the jaws while simultaneously drawing the clip pusher bar in an opposite direction to prepare for feeding the next clip in the series of clips to the jaw mechanism. This arrangement typically requires additional moving parts, also tending to increase the cost of manufacture and increase the time of assembly.
The need therefore exists for an instrument for applying surgical clips which reduces the number of parts, and consequently reduces the cost of the instrument, while at the same time reducing the amount of time needed to assemble the instrument during manufacture. A specific need exists for an instrument which minimizes the number of moving parts and synchronizes the moving parts so that they move in the same direction upon closing and opening of the handles. By minimizing the number of moving parts, and synchronizing the direction of movement of the moving parts, the instrument becomes sturdier and easier to manipulate during the surgical procedure.
The need also exists for an instrument having a lockout mechanism which both prevents closing of the jaws by providing a reliable blocking mechanism, while at the same time providing a mechanism for rendering the instrument inoperable upon the application of a predetermined force to the handles after all the clips in the instrument have been utilized during the surgical procedure.